1. Field of the Invention
The invention pertains to a composition comprising phospholipid, surfactant and, optionally, iron compounds, for treating groundwater contamination. The invention further concerns a method for remediation of contaminated groundwater through bioremediation comprising the step of applying, at least, the composition to contaminated groundwater. The composition and method may be used for treating groundwater contaminated with halogenated organic compounds, such as chlorinated ethenes and methanes, as well as other types of contaminants.
2. The Related Art
Groundwater contamination can be remediated by physical means, such as the removal of contaminated groundwater from an aquifer followed by removal of contaminants, i.e. pump and treat methods. Other methods, such as in situ remediation techniques through chemical oxidation and bioremediation have also been developed.
Pump and treat methods generally involve installing one or more recovery wells to recover contaminated groundwater from an aquifer and then removing the contaminants with above ground treatment, such as by air stripping and/or activated carbon adsorption. The decontaminated water is then usually discharged to a surface water body, possibly after further treatment by a water treatment works. The in-situ methods discussed above (i.e. chemical oxidation and bioremediation) are considered cost effective remedial alternatives, particularly when conventional pump and treat methods are ineffective because a particular geological system has low permeability.
Chemical oxidation methods generally involve injecting chemicals into a contaminant plume in the groundwater which react with the contaminants to convert the contaminants into substances that are not harmful to the environment. Biological methods, such as bioremediation, involve the use of biological organisms to remediate the contaminants via a process generally referred to as biodegradation.
U.S. Pat. No. 6,398,960 concerns a method for the bioremediation of contaminated groundwater, which is said to remediate the groundwater using an innocuous of oil formulated into a microemulsion by mixing with one or more natural food-grade emulsifiers and water. Also, chlorinated solvents can be remediated through a method of bioremediation involving the use of polyacetate esters which release lactic acid that is metabolized by microorganisms to produce hydrogen ion. Remediation of contamination with zerovalent iron, such as nano iron, i.e. extremely fine nano scale (10−9 meter) iron particles, is also discussed in the art.
New and more efficient technologies for remediation of water, such as groundwater, are constantly desired in the art. Moreover, remediation technologies efficient to particular classes or types of contaminants are also desired because the type and nature of contaminants in groundwater may differ depending on the nature of the activities conducted at industrial and commercial establishments at or near the groundwater contamination, and the nature of the toxic substances in the groundwater.
All parts and percentages in this specification and the claims are on a weight by weight basis unless otherwise specified.